Effect of Silk-Fibroin-Coated Polydioxanone Biodegradable Enteric Stents on the Degradation Rate

Biodegradable enteric stents have limited use in benign enteric stricture due to the short degradation time. Silk fibroin (SF) coating on polydioxanone (PDO) has been proposed to extend the degradation rate. PDO stents and yarn were coated with SF solution by using the dip-coating method. Surface properties of the SF-coated PDO yarn were observed by scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle analysis. The degradation of the uncoated and 0.5% SF-coated PDO stents were compared at 4, 8, 12, and 16 weeks after incubation. The 0.5% SF-coated PDO stent showed a significant delay in the degradation rate (remaining weight 98.87 and 93.31% at 4 and 8 weeks versus 91.21 and 88.34% in the noncoated stent). After 8 weeks of incubation, the radial compressive force remained in SF-coated stents, while the uncoated stents were destroyed. The bicinchoninic acid assay of the supernatant fluid confirmed an increased amount of dissolved SF in a linear fashion. In conclusion, SF coating on PDO stents using the dip-coating method and fixing with liquid nitrogen could delay the degradation rate of the biodegradable stent and prolong the stent shape retention up to 4 weeks after incubation when compared with an uncoated stent.